Presently, various methods and holders are known with which photovoltaic systems are installed, also in particular on flat roofs. What matters in each event is a solid, in particular windproof, holder of the photovoltaic systems of solar collectors on the roof. Accordingly, it has been proposed to anchor the holders in the roof surface via drilled holes. This, however, has the disadvantage that, at the drill holes, the drill holes destroy the existing roof sealing that is typically established by bitumen panels. As a result, leaks in the roof surface can disadvantageously be caused. This problem is particularly significant for flat roofs. Further, in order not to create leaks in the roof surface, it has been proposed to fasten the holders on the side walls of the building, for instance via T-beams. This method, however, is disadvantageously very cost intense and also affects the outside appearance of the building in a frequently undesired way.
Finally, it is known to fasten the holders on the roof surface with weights. This, however has the disadvantage that the maximum snow load that the roof can bear is reduced by the mass of the holder and of the weights used for fastening it. If the roof is not otherwise additionally reinforced, a critical snow load can consequently disadvantageously already be reached with a small amount of snow.
Due to the problems and shortcomings of the known holders and methods of mounting them, solar technology has been rarely utilized in particular on flat roofs.